604

Power down the machine completely. Inspect all FSSB cable connections at the servo amplifier module (SVM) and at the PSM/control unit. Ensure the orange fiber optic cables are fully seated and locking tabs are engaged.

Do not bend FSSB cables at radius less than 40mm. Disconnect power before handling cables.

Check FSSB cable for visible damage including kinks, excessive bending, cuts, or contamination at the optical connectors. Clean optical connectors with lint-free swabs and isopropyl alcohol if contamination is present.

Never look directly into fiber optic cable ends while power is applied - laser light can damage eyes.

Replace FSSB cables one at a time if damage is found. After reconnection, power up and check LED status on the servo amplifier. LED 'FSSB' should be steady green. Flashing red indicates continued communication error.

Navigate to DIAGNOSIS > SERVO > and check FSSB communication status for the affected axis. Parameter 8181 (FSSB channel assignment) should show correct axis allocation. Verify alarm clears after cable replacement.

Check the servo amplifier LED diagnostic indicators. Power LED should be green, ALARM LED should be off. If ALARM LED is red or FSSB LED is off/flashing red, amplifier has internal fault. Record LED pattern for diagnosis.

Navigate to DIAGNOSIS > SERVO > and check diagnostic screens D0700-D0799 (servo alarm history). Look for preceding alarms like AL-37 (serial pulse coder comm error) or AL-50 (overheat) that may indicate amplifier hardware failure.

Verify DC bus voltage at the amplifier. Check parameters 2165 (regenerative load level) and diagnostic D0041 (DC link voltage). Voltage should be 280-310VDC for 200V class. Low or unstable bus voltage indicates PSM or amplifier power section failure.

High voltage present - use appropriate safety procedures and PPE.

If all FSSB cables test good and LED indicates amplifier fault, replace the servo amplifier module. After replacement, set parameter 1815#0 (absolute position lost) to 1 and re-establish reference position for the axis.

Record all axis servo parameters before amplifier replacement for verification after installation.

Check if alarm 604 occurs on single axis or multiple axes. Multiple simultaneous 604 alarms suggest PSM or control unit FSSB master failure rather than individual amplifier issue. Check PSM LED status - POWER should be green, ALM should be off.

Navigate to MAINTENANCE > BOARD TEST and run FSSB communication self-diagnostic if available on your control series. Check parameter 8181 (FSSB axis assignment) and 8183 (FSSB transmission speed) for corruption. Default 8183 should be 2 (high-speed mode).

Swap FSSB cable connections between working and faulted axis at the PSM to determine if fault follows cable or remains with channel. If fault stays with PSM channel, PSM FSSB interface board requires replacement.

Perform cable swapping only with power completely removed. Label all cables before disconnection.